package com.autumn.platform.core.crypto;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;
import java.security.spec.InvalidKeySpecException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class DESUtils extends CryptoUtils {

    private final static String KEY_ALGORITHM = "DES";

    public static String encrypt(String plainText, String key) {
        try {
            SecretKey securekey = getSecretKey(key);
            Cipher cipher = getCipher(KEY_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, securekey, random);
            byte[] bt = cipher.doFinal(plainText.getBytes());
            return encodeToString(bt);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        }
    }

    public static String decrypt(String encryptText, String key) {
        try {
            SecretKey securekey = getSecretKey(key);
            Cipher cipher = getCipher(KEY_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, securekey, random);
            byte[] datas = cipher.doFinal(decodeFromString(encryptText));
            return new String(datas);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        }
    }

    private static SecretKey getSecretKey(String key) throws InvalidKeyException {
        try {
            byte[] datas = key.getBytes();
            DESKeySpec dks = new DESKeySpec(datas);
            Provider provider = getProvider();
            SecretKeyFactory keyFactory = null;
            if (null == provider) {
                keyFactory = SecretKeyFactory.getInstance(KEY_ALGORITHM);
            } else {
                keyFactory = SecretKeyFactory.getInstance(KEY_ALGORITHM, provider);
            }
            SecretKey securekey = keyFactory.generateSecret(dks);
            return securekey;
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeySpecException e) {
            throw new RuntimeException(e);
        }
    }
}
